Safety ski bindings



April 21, 1964 R. LUSSER SAFETY SKI BINDINGS 5 Sheets-Sheet 1 FiledSept. 15, 1962 April 21, 1964 R. LUSSER SAFETY SKI BINDINGS 5Sheets-Sheet 2 Filed Sept. 13, 1962 April 21, 1964 R. LUSSER 3,129,951

SAFETY SKI BINDINGS Filed Sept. 15, 1962 5 Sheets-Sheet 3 Aprzl 21, 1964R. LUSSER 3,129,951

SAFETY SKI BINDINGS Filed Sept. 13, 1962 5 Sheets-Sheet 4 A ril 21, 1964R. LUSSER 3,129,951

SAFETY SKI BINDINGS Filed Sept. 1:5, 1962 5 Sheets-Sheet 5 United StatesPatent 3,129,951 SAFETY SK! BINDINGS Robert Lusser, Steinhauserstr. 27,Munich, Germany Filed Sept. 13, 1962, Ser. No. 223,394 Claims priority,application Germany Sept. 18, 1961 12 Claims. (Cl. ass-41.35

The present invention relates to safety bindings for ski boots and moreparticularly to safety bindings which, when the skier falls, willautomatically open if a predetermined tension at the heel, or leg whichwas selected for preventing injury to the skier is exceeded.

There is known a safety binding in which the toe of the ski boot sole issupported against a fixed clamp mounted on the ski, and a pressuremember which extends in a generally oblique direction from the reardownward toward the front of the ski presses rearwardly upon the heelportion of the sole. This pressure member is hinged to one end of atwo-armed lever so as to swing in a vertical longitudinal plane, withthe two-armed lever being mounted on the ski in such a fashion that suchlever can also swing in a vertical longitudinal plane. At the other endof the two-armed lever, tension spring means engages in such a directionthat it tends to press the free end of the pressure member into afitting mounted on the heel portion. Thus the heel of the ski boot ispressed upon the ski by the pressure member which is acted upon by thespring means.

When the pull on the heel and the leg becomes greater than the verticalcomponent of the force exerted obliquely by the pressure member on theheel portion, the heel portion begins to separate from the ski. With theraising of the heel portion, the vertical component of the force exertedby the pressure member initially increases due to the increasing springtension, but since with the raising of the heel portion the inclinationof the pressure member becomes increasingly flatter, a point is reachedafter which the magnitude of the vertical component which endeavors toreturn the heel portion onto the ski decreases in spite of the increasedspring tension. If the pull of the heel portion becomes so great thatthe heel portion reaches such instable point, the heel portion willcontinue to move further, thereby freeing itself from the ski.

The advantage of such a binding resides in releasing the boot completelywhen the safe load of the heel portion is exceeded, and that suchreleasing point can be predetermined with safety. The length of the pathin which the heel portion can move away from the ski prior todisengagement of the binding, the force by which the heel portion isheld to the ski, and the force at the moment of release, depend on theinclination or angularity of the pressure member, the length of thepressure member, the pivot point of the lever, and the tension of thespring.

In the known ski safety binding, adjustments can be made, in the tensionof the spring and in the horizontal distance between the pivot point ofthe level and the heel portion of the boot and thus in the inclinationof the pressure member. By changing the spring tension, the force can beselected at which the heel portion will begin to lift from the ski, butthe path which the heel portion must travel to reach the point ofdisengagement is not changed materially. Since the kinematics remain thesame with a change in the spring pretensioning, the char acteristic ofthe force increase with the raising of the boot heel portion from theski also remains the same. It begins only at a greater or smaller force.If the horizontal distance between the pivot point of the lever and theheel portion is increased, and thus the inclination of the pressuremember is decreased, then, at the same pretension of the spring means,the vertical pressure component of the force endeavoring to hold theheel portion on the ski and acting from the pressure member on the heelportion will become less, and, due to the change in kinematics, thecharacteristic of the increase of force with the raising of the heelportion from the ski will become flatter. At the same time the pathtraversed by the heel portion in raising from the ski until it movespast the unstable point becomes shorter. However, a fiat rise of forcewith a small initial force is desired only for cross-country runs andfor climbing, but, at the same time, it is desirable that the heelportion can be raised quite far from the ski without the bindingopening.

in the known safety binding, the two above noted adjustmentpossibilities are provided only for the purpose of being able to adaptthe force by which the heel portion is held upon the ski and thereleasing force to the physical constitution of the skier. It is muchmore important, however, that each skier can readily adapt his bindingby a simple manipulation to the various, completely differentrequirements in skiing down-hill on the one hand, and in skiingcross-country or climbing on the other hand. In a down-hill run, theheel portion should be held firmly on the ski and should raise from theski only at a greater pull of the heel portion. For example, whenfalling forward, if the pull of the heel portion exceeds a predeterminedsafety value or factor, then the boot should disengage quickly from theski. To alford the skier the feeling to note that the pull of the heelportion approaches the pre-determined releasing forge, only a short pathis desired for the heel portion to the point of release, but with asteep rise in force. It is not desirable in a downhill run that the heelmust initially travel a long path with increasing restoring force beforethe heel portion can disengage from the ski. On the other hand, inclimbing or in cross-country skiing, the pre-tension by which the heelportion is held to the ski should be small, but the path great which theheel portion can traverse in raising from the ski until the point ofrelease is reached.

The requirements above mentioned are fulfilled if the known ski safetybinding is developed further in accordance with present invention, sothat the spring engages a selector lever mounted on the lever, or on thepressure member and is swingable between two stops, with the pivot pointof the selector lever being so positioned that the spring loads theselector lever for pressure and that, in the position of the latter awayfrom the lever pivot point, for a down-hill run, the selector leverpivot point moves across the connecting line of the two springsuspension points if the raising of the boot heel portion from the skiexceeds a predetermined distance of travel, so that when this traveldistance is exceeded, the selector lever moves automatically into theposition near the lever pivot point, for climbing or cross-countryskiing, and in which position the pressure member presses upon the heelportion with less force.

When the skier has placed the selector lever into the position near thelever pivot point, the spring engages at a smaller lever arm than in theother position away from the lever pivot point. Thus, in the positionnear the lever pivot point, the heel portion is held on the ski withless force, and with the raising of the heel portion from the ski suchforce rises more flatly than in the position away from the lever pivotpoint. The first-noted position is provided for climbing orcross-country skiing, and in such skiing, the skier should be able toraise his boot heel from the ski quite a distance without much force.The disengagement of the heel portion takes place in the same manner asdescribed above in reference to the known ski safety binding.

When the skier desires to start downhill, he merely needs to swing, onboth of his skis, the selector lever into the position away from thelever pivot point, and in which position the spring engages a largelever arm. In that position, the force of the spring acts upon the bootheel portion several times more strongly, and the heel portion is heldon the ski with great force. When the pull of the heel portion becomesgreater than that force, the heel portion raises from the ski, but theskier will feel a steep rise in force which indicates to him when thebinding approaches the disengagement point. When the heel portion hasbeen raised from the ski a certain distance determined by the positionof the selector lever pivot point, the selector lever pivot point movespast the connecting line of the two spring suspension points, i.e.,

past its dead center. Therefore, immediately after exceeding thisraising distance of the heel portion the selector lever willautomatically snap from the position away from the lever pivot pointinto the position near the lever pivot point. From this point on, theforce tending to return the heel portion onto the ski equals the verymuch smaller force for climbing and cross-country skiing.

If with the position of the selector levers of the two bindings set fora downhill run, the skier falls forward and hence the safe pulling forcefor his heel and his leg is exceeded, the selector lever snapsautomatically into the climbing or cross-country position. Sincetherewith the force tending to return the heel portion upon the ski issuddenly reduced very strongly, the heel portion will continue to movefurther until it is completely freed from the binding and thus from theski. Consequently, the skier can, without unbuckling the ski and withoutany cumbersome adjustment, adjust his binding very simply by merelyshifting a lever into the position for a downhill run or into theposition for climbing or cross-country skiing. In each position, themagnitude and the characteristic of the force tending to hold the heelportion on the ski corresponds to the physical constitution of theskier, and in both positions any excess strain on the heel, 'or the legof the skier in a fall is positively avoided.

The invention and further objects and advantages thereof will becomeapparent from the ensuing description and annexed drawings illustratingseveral embodiments of the invention by way of example.

FIG. 1 is a side elevational view of a ski safety binding according tothe basic principle of the invention.

FIG. 1a is a diagrammatic View of the path of force in raising the heelportion away from the ski.

FIG. 2 is a view along the lines of FIG. 1 showing the first furtherdevelopment of the ski safety binding according to the invention.

FIG. 2a is a diagrammatic view of the path of force with the binding ofFIG. 2.

FIG. 3 is a view along the lines of FIG. 1 showing the second furtherdevelopment of the safety binding according to the invention.

FIG. 3a is a diagrammatic view of the path of force with the binding ofFIG. 3.

FIG. 4 is a side elevational View of yet another embodiment of a skisafety binding according to the invention.

FIG. 5 is an elevational view, partly broken away of a ski safetybinding constructed according to the invention.

FIG. 6 is a cross section taken along line A-B of FIG. 5, the viewlooking in the direction of the arrows.

FIG. 7 is an elevational view showing the safety binding of FIG. 5immediately before disengagement.

FIG. 8 is a rear elevational view of the heel fitting used with thebinding.

FIG. 9 is a diagrammatic view of the force acting vertically upon theheel, superimposed over the lifting path of the heel from the ski.

FIG. 10 is a side elevational view partly in cross section, of apreferred embodiment of the invention.

FIG. 11 is a cross section taken along line CD of FIG. 10, the viewlooking in the direction of the arrows.

FIG. 12 is an elevational view of the ski safety binding of FIG. 10immediately prior to the attachment to the heel fitting.

FIG. 13 is an elevational view of the safety binding according to FIG.10 in the position for a downhill run.

FIG. 14 is an elevational view showing the binding set for the downhillrun immediately prior to the switchover into the climbing position, and

FIG. 15 is an elevational view of the same binding immediately prior tothe release of the ski boot.

In FIG. 1, a ski is denoted 1 and sole 2 of a ski boot 3 coacts at toeportion 4 with a known torsion toe clamp 5 attached to the ski and whichreleases the boot at the toe of the sole when the torsional force actingin the leg exceeds a predetermined safe factor or value.

Into a recess or socket 6, preferably reinforced by a fitting (notshown), at the heel portion 7 of the sole 2 is engaged one end of apressure member 8 which extends from the recess 6 in an oblique rearwardand upward direction and which is pivoted at its other end to a lever 10by pivot pin 9. The lever 10 in turn is swingably mounted by a pivot pin11 to a bracket 13 fastened to a base plate 12 which is secured to theski by screws or the like (not shown). The lever 10 is provided with anextension 14 which projects downwardly and a selector lever 16 ismounted thereon by means of a link pin 15. The selector lever 16 isdefined by two legs, one leg being disposed on each side of the lever10, with the legs being connected at their outer ends by a bolt 17. Theends of the bolt project beyond the legs of the lever 16. At each of thelateral projections of the bolt 17 there is suspended a tension spring18 and the lower end of the spring is connected to an eye 19 on the baseplate 12.

The rearward end position of the selector lever 16 is determined by thebolt 17 resting upon the upper edge of the lever 10, and the forward endposition by the selector lever abutting against the upper end of thepressure member 8.

In the position of the selector lever shown in FIG. 1

in full lines, the spring 18 acts on the long lever arm L upon the lever10, while in the rearward position adjacent the pivot pin 11, shown indotted lines, the spring 18 acts only upon a small lever arm L.Depending on the vari able length of the lever arm by which the spring18 acts upon the lever 10, the force in also variable at which thegressure member 8 presses upon the heel portion 7 of the cot 3.

In FIG. la there is shown diagrammatically the vertical component ofthat force which tends solely to return the heel portion 7 upon theski 1. Legend I designates the vertical force component with which theheel portion is held to the ski 1 in the downhill position of thebinding, and legend II the vertical force component with which the heelis held to the ski 1 in the climbing or cross-country position of thebinding.

For illustrative purposes it is assumed that the selector lever 16 is inthe position adjacent the lever pivot pin 11 (as shown in dotted linesin FIG. 1), and in which position the spring 18 acts upon the smalllever arm L. In this position, the boot heel portion 7 is held on theski 1 only with the relatively small force II. In climbing orcross-country skiing, the skier needs to employ merely the small forceII in order to raise the heel portion 7 from the ski 1. After raisingthe heel, the force tending to hold the heel portion 7 upon the ski 1increases fiatly along the curve a. In that position, the ski safetybinding functions like the above-mentioned known safety binding.Although the force of the spring 13 increases with the raising of theheel portion 7, the vertical force component tending solely to returnthe heel portion 7 upon the ski 1, will because of the increasinglystronger inclination of the pressure member 8 attain a maximum asindicated at legend III. When the heel portion is raised so far that thevertical force component has attained the maximum value III, the heelportion 7 will be in an unstable position. H the skier exerts a somewhatgreater pull with his leg, the heel portion will move beyond the pointIII. Since from this point onward the force tending to return the heelportion to the ski decreases again, the heel portion will continue tomove further under the force effective in the leg until it is completelyfreed from the pressure member 8.

If the skier desires to make a downhill run, the selector lever 16 isplaced in the position away from the pivot pin 11 (as shown in fulllines in FIG. 1). In that position, the heel portion 7 is held on theski 1 with the greater force I. If the pulling force exerted by theAchilles tendon of the leg upon the heel exceeds the force I, such as,for example, when the skier leans forward, then the heel portion 7 willrise from the ski I. The farther the heel 7 moves away from the ski, themore the vertical component of the force exerted by the pressure member8 upon the heel portion 7 will increase. This rise in force isdesignated in FIG. la at b. With the raising of the heel portion 7 fromthe ski 1, the bolt 17 and the pin 15 of the selector lever 16 will movealong a circular path around the pivot pin 11 of the lever It). Thus, aposition of the lever 14) is attained in which the center of the bolt17, the geometrical axis of the pin 15 and the eye 19 are all in oneline, whereby the selector lever 16 assumes a dead-center position. Thevertical force component acting in that position on the heel portion isdesignated in FIG. 1a by legend IV. When the pull of the heel portionexceeds the force IV, the connecting line between the two suspensionpoints of the spring 18 travels across the geometrical axis of the pin15, with the result that the spring 18 swings the selector lever 16 intothe rearward position adjacent the lever pivot pin 11. Thus, thevertical force component acting on the heel portion drops immediately tothe legend V on the curve a which describes the course of the verticalforce compo nent tending to return the heel portion 7 to the ski in theclimbing or cross-country position of the binding. Since at that moment,the force exerted by the pressure member 8 upon the heel portion 7 issuddenly strongly reduced, the pulling force exerted by the body on theskiers leg outweighs at that particular moment. The result is that theheel portion moves farther away from the ski and is released, asdescribed above from the bind ing at the point III.

The point III in the force pattern is reached before the pressure member8 and the rearward part of the sole 2 have reached a stretched positionrelative to each other. If the path which the heel portion traverses toattain this point is too short for climbing or cross-country skiing, andif a longer lift path is desired then a limiting device can be included.

The limiting device serves to hold the member 8 fixedly at apredetermined angle relative to the lever 19 whereby the pressure member8 can no longer swing freely upwardly as in FIG. 1. The end angleposition can be delimited rigidly by a fixed stop (not shown) or, asillus trated in FIGS. and 12 at 326 by means of a flexible butnon-stretchable tension member.

As shown in FIG. 2, a spring 21 can be anchored in an eye 22 on the baseplate 12 and is connected at its free end to a hole 23 of the pressuremember 8. Otherwise,

6 the ski safety binding of FIG. 2 is similar to that shown in FIG. 1.

Since the center line of the spring 21 in the initial position of thebinding embraces only a small angle with respect to the ski, it isbarely efiective at the initial raising of the heel portion from the skiso that the force pattern b in the downhill run and the beginning of theforce pattern a in the climbing or cross-country skiing of FIG. 2a aresimilar to the corresponding force patterns of FIG. 1. However, thecloser the pressure member 8 and the rear portion of the sole 2 approachthe stretched position, the greater the effect of the spring 21 becomes.The curve a no longer attains a maximum and then again drops off, butrather the vertical force component tending to bring the heel portionupon the ski increases steadily, and increasingly steeper, until thestretched position of pressure member 8 and the rear portion of the sole2 is exceeded and, with attainment of force III, the free end of themember 8 moves from the recess 6 of the heel 7 since with a furtherlifting of the heel, the end of the member 8 moves approximately alongpath 2 2- and the recess 6 in the heel portion along path 25.

The binding shown in FIG. 3 differs from that of FIG. 2 only in that aloose cable 26 is inserted between tension spring 21a and the pressuremember 8. The binding so made acts initially exactly like the binding ofFIG. 1. The cable member 26 interposed between the end of spring 21 anda hole 23 in the pressure memher 8 is of such a length that it willbecome taut at about, or shortly after, that position of the binding atwhich the force tending to return heel portion 7 to the ski attains theunstable point III of FIG. 1a. From that point on, the force pattern ofthis binding changes as compared to that of FIG. 1. Depending on theselection of the spring 21a, the force will rise more or less steeplyfrom that point up to the point III" at which the recess 6 in the heelportion 7 will separate from the free end of the pressure member 8 asdescribed in connection with FIG. 2.

The binding in FIG. 3, possesses the advantage that in the climbing andcross-country position of the selector lever 16, the force tending topull the heel portion onto the ski increases only slightly within thenormal range of the movement of the heel portion and therefore it isunnecessary for the skier to expend appreciable effort in climbing or incross-country skiing. But, when the heel portion approaches thereleasing position III", the force rises steeply so that the skiersenses that he is now approaching the releasing position of the binding.For practical purposes, the magnitude of the force III" can be selectedjust about as great as the force IV, but will as a rule probably beselected somewhat smaller.

If, with the binding in FIG. 3, and the position of selector lever 16 inthe down-hill position (in the position away from the pivot point of thelever), the skier should fall forward, the force will rise initiallyfrom I to IV along the curve b. There, as has been described inconnection with FIG. 1, the selector lever will shift automatically intothe climbing or cross-country position, so that the force now drops fromIV to V. The result of the foregoing is that the force now along theline a is no longer suihcient to return the heel portion to the ski, andthe skier will continue to fall further forward. Hence the force risesagain steeply at the end, but due to the kinetic energy possessed by theskier the pressure member 8 will, despite the force acting thereon inthe opposite direction be jerked upward by the heel portion 7 untilpoint III is reached and the heel portion is released from the binding.

Referring to FIG. 4 there is shown a binding which in principle issimilar to that of FIG. 2. In the binding in FIG. 2, in every positionof the binding, there is transmitted from the sprin 18 to the pressuremember 8 a force acting in the direction of the connecting line hetweenthe pivot pin 9 and thesupporting point of the end of the pressuremember 8 in the recess 6, which force can be combined with the force ofspring 21 into a resultant force which engages at connection 23.Proceeding fromthis concept there is provided in FIG. 4 only a singlespring 28 which acts by way of a selector lever 16a upon pressure member3a. Here also, the pressure member 8a is connected by a pivot pin 59 tothe end of a lever 10a which can swing relative to bracket 13a fastenedto the ski 1. The pressure member 8a is U-shaped in cross section and isopen downwardly. The selector lever 16a is provided at the free end witha pin 17a which projects through a slot 29 in the wall of the pressuremember 8a. Between the two side walls of the pressure member 3a theupper end of pressure spring 28 is connected to the bolt 17a. By theco-action of the bolt 17a with the ends of the slot 29 are determinedthe two positions of the selector lever 16a which include a handlemember 16!) so as to be able to move the same easily from one positionto the other, position. Also with such binding the force tending to holdthe heel portion on the ski is greater at the position of the lever 16aadjacent the heel portion than at the position remote from the heelportion. Here again the selector lever snaps automatically, after theraising of the heel portion from the position adjacent the heel portioninto the position remote from such portion. The force pattern isgenerally similar to that illustrated in FIG. 2a.

With reference to FIGS. and 6, there is shown a binding according to thebasic principle of FIG. 1 as regards its details. There is mounted onthe ski rearwardly of the heel portion base plate 112 carrying the ski bnding. A bracket 113 extends upwardly from plate 112 and is provided atits upper end with a slot 131 for forming a fork. The lever 11% ispivotally connected to the upper end of the bracket 113 by bolt means111. A pressure member 108 is connected to the free end of the lever 110by a transversely extending bolt 109 and free end 1055a which isgenerally cylindrical engages recess 166 of a fitting 106a attached tothe rear end of the heel portion 7 of the ski boot. The axis of the end168a extends transversely to that of the ski 1; the end of 1128a, ifdesired, may be in the configuration of a sphere. Selector lever 116 isof approximately U-shape with the legs thereof being positioned on theopposite sides of the lever 110. At the lower ends of the legs of thelever 116 are provided pivot pins 115 which project inwardly and engagea bore in the lever 11%), with the same being held in the bore by virtueof the rigidity of the lever 116. A handle 116a is provided for thelever 116 and is in the form of a disk having lens-shaped recesses onthe respective sides thereof. A substantially fork-shaped cross-piece1116b of the lever 116 is extended on each side of the lever and theterminal ends are bent in a downward direction.

Each terminal end is provided with a bore 133 in which is lodged anupper hook 134 of tension spring 113. At its lower end, the spring isconnected by means of a hook 135 to a pin 136 which is inserted into twoeyes 119 extending upwardly from the base plate 112. The rearwardposition II of the selector lever 116 shown in FIG. 5 by full lines isdetermined by its abutment against the bracket 113. The position I ofthe lever 116 provided for the down-hill run is determined by itsstriking cheek 168k of the pressure member 108.

In departure from the binding of FIG. 1, there is attached in FIGS. 5and 6 at each side of the lever 110 by rivets a generally angle-shapedspring shoe 137, free leg 138 of which is positioned behind the spring118 when the spring is in the climbing position. The leg 138 of eachshoe, as can be seen in FIGS. 5 and 6, has a curved shape.

Upper edge 139 of the'lever 110 in the range of the pivotal movement ofthe selector lever 116 is provided with a contour corresponding to acircular are around the center. of the pin 115, so that during theswinging of the lever 116 the distance between the component 11617 ofthe selector lever and the upper edge 1315 of the lever remains constantand that a jamming of the glove is prevented during adjustment of theselector lever. The lever 110 which, because of this construction, has arelatively large surface, includes a large aperture 14% which, inaddition to a material saving in weight, serves at the same time as ahandheld for moving the lever 110 when, in attaching the binding, theskier desires to bring the pressure member 198 into the recess of theheel fitting 106a.

The heel fitting 166a is provided with an angular lug or the like 143which engages the top heel portion of the sole and has two fasteningholes for the reception of screws 144 which pass transversely throughthe material of the heel. The angular lug 143 transmits the verticalpressure component exerted on the recess 196 directly to the heelportion. The screws 144 serve, therefore, merely as fastening means anddo not have to transmit any force so that there exists no danger of thefitting 106:: being torn from the heel portion of the boot sole.

For attaching the binding, the selector lever 116 is initially swunginto the position 11 adjacent the pivot pin III. Then, the lever 11% canbe moved by placing a finger in the opening 146, and in this regard, atthe same time, the finger can press on the cheek 10% of the pressuremember thereby forcing the pressure member 163 in the direction of theheel, so that with the raising of the lever 11th, the end 1138a of themember 1113 engages the recess 106 of the heel fitting, whereby thebinding is fully attached.

As shown in FIG. 9, the binding presses vertically upon the heel portionwith a force of about 3 kg., and if'the skier in climbing orcross-country skiing lifts the heel up from the ski, then the lever 116will swing upward and the two springs 11% become tensioned. .As apparentfrom FIG. 5, in such regard the force k of the two springs 118 acts uponsmall lever arm l If the spring shoes 137, 138 were not provided, thevertical force component acting on the heel portion would have a pathsuch as is shown at a in FIG. la and in FIG. 9. As already described, inconnection with FIG. 1a, the force rises only relatively flatly alongthe curve a up to the unstable point III. It is assumed in connectionwith FIGS. 5 and 6 that the skier desires clear indication he isapproaching the unstable point 111 and hence the releasing point of thebinding and this is obtained by the spring shoes 137, 138. The effect ofthe spring shoe can be seen in FIG. 7. As soon as the heel portion 7 israised about 2 centimeters from the ski the leg 138 of the spring shoe137 abuts against the spring 118 and presses the spring with a furtherswinging of the lever 110 in an intermediate zone between its twosuspension points increasingly out of its stretched position so that thespring force now increases more rapidly and moreover engages a lever armwhich becomes increasingly larger. The result is that the verticalpressure component exerted by the member 108 upon the heel portion 7takes the course [1 In that course, the force increases flatly at firstand then, when it approaches the releasing point, increases more steeplyuntil, at about 6 cm. of the lift path of the heel, it reaches releasingpoint III" with 50 kg. Thus, if the skier, for example while fallingforward, pulls the heel upwardly with a tension force of more than 50kg, the heel, after exceeding a path of 6 cm., will automatically bereleased from the binding.

If the skier desires to make a downhill run, he places the selectorlever 116 into the position I. In such position, the spring force k actson the lever arm l and as seen in FIG. 9, the heel portion is held onthe ski with a force of 30 kg. Now, if the skier falls forward, forexample if he hits an obstacle or gets into deep snow, the heel portionwill be jerked upward. As explained in connection with FIG. la, in sucha case the vertical pressure k component increases at first toward theline b, until after a very short lift path of only about 2 cm., thelever 110 with the selector lever 116 has reached a position in whichthe upper suspension point 133 of the spring 118 lies in the extensionof a line between the suspension point 119 of the spring and the pivotpoint 115 of the selector lever. When such unstable point is passed, thespring 118 pulls the selector lever 116 into the position 11. Thus,after the vertical pressure component has, with a lift path of 2 cm.,attained about 100 kg. at point IV, which is assumed in the selectedexample as the maximum admissible stressing of the Achilles tendon, thepressure component tending to press the heel upon the ski will drop oifsuddenly to about 5 kg. at point V and, if the fall forward continuesfurther, will rise again to about 50 kg. at point 111" at a lift path ofabout 6 cm. before the heel portion will be released from the binding.It is apparent from the above that in a fall forward a tension force of100 kg, respectively 30 kg, on the Achilles tendon can never beexceeded. The assumed maidmum force of 100 kg. is set with respect to anexperienced skier, and for skiers of normal constitution and forchildren, the springs 118 are exchanged for weaker springs.

In order that, with the lifting of the heel portion from the ski and afall forward, the unstable position corresponding to point 1V shall beexceeded safely and quickly, the pressure member 1% is provided with anose portion 1030 which coacts with the front edge 1160, for pressingthe selector lever positively beyond the unstable position.

In FIGS. 10 and 11 there is illustrated the details of a ski safetybinding constructed according to the principle explained in regard toFIG. 3. In this embodiment, base plate 212 is slidable longitudinally ofthe ski in a guide plate 252 mounted on the ski 1 by screws 251. Athreaded socket 293 is welded to the base plate for the reception of alocking screw 2114. The screw 204 is provided with a pointed end whichcan engage one of the conical recesses 295 in the guide plate 252 forfixing the base plate 212 in a definite position relative to the guideplate 252. By virtue of this arrangement, the ski safety binding can beadjusted at a variable distance from the customary toe clamp mounted infront of the boot and can thereby be adapted to boots of differentsizes. Bracket 213 mounted on the base plate 212 is provided adjacentthe top with a slot 231 which forms a fork adapted to engage the lever211 which is pivoted to the bracket 213 by a pivot bolt or pin 211. Thestrongly designed lever 21% is provided at its end with a bore in whichis mounted pivot pin 209 of a pressure member 208, and the pin 2 .39 isin the form of a hollow cylinder. The pressure member 208 is providedwith a slot 255 so that the upper end is shaped in the nature of a fork.At the lower end of the member 2113 is formed a cylinder 2418:: having atransversely extending axis which cylinder is adapted to engagecorrespondingly formed recess 2% of the heel fitting 2116a.

The lever 21! is of arcuate configuration, with the convex edge beingdownward. A fork-shaped selector lever 216 is swingably mounted to thelowest point of the lever 210 by a pivot pin 215. The lever 216 isformed at its outer end with a transversely extending U-shaped recess216a, in which is positioned the central part of a U-shaped bolt 217.Each of the two legs of the bolt 217 is provided with a thread 217a andis threaded into a threaded socket 256. The socket 255 is formed with anexterior thread conforming to the convolutions of the helical spring 213and defining the upper mounting component for the suspended spring 213.The uppermost convolutions of the spring are threaded about the socketwith a radial pretensioning. Each spring 218 is provided at its lowerend with a hook 235 which engages an eye 219 secured to the base plate212.

t a point located between the ends of the spring 218, a stiff cable 226is passed between two adjacent convolutions, with the end of the cableextending into the sprin The end of the cable is provided with a bulgeor protuberance 226a which may be soldered or pressed onto the cableend. The bulge prevents the end of the cable from being withdrawnbetween the convolutions of the spring 1b 218. The cable 225 extendsfrom one spring 213 through an aperture 223 in the pressure member 2133to the spring 218 on the other side of the binding. The cable 226 tendsto straighten and thus swing the pressure member 208 in a directiontoward the heel portion 7. Instead of a relatively stiff wire-strandcable, it is possible, for example, to employ a chain composed of twolinks. In such situation, the movement of the pressure member in thedirection of the heel portion can be eifected by means of a torsionspring which tends to force the pressure member away from the leverforward toward the heel portion.

A flange 258 extends upward from the forward end of the base plate 212and includes a slot 259 which widens out somewhat toward the top. Theflange 258 can be curved so as to adapt itself to the contour of theheel portion of the boot. The fitting 206a which is secured to the heelportion 7 fits into the slot 259. The function of the slot 259 is formaintaining the heel portion 7 firmly centered on the ski during tiltingof the ski and during the so called Wig-wagging, against the stronglateral force active during those conditions. In addition, the slot 259assures that the heel, after it has been raised, will always return intothe central position on the ski, and any lateral play still existing isautomatically eliminated thereby.

In lieu of the heel fitting 2%a, or in addition thereto, another part ofthe binding, such as the pressure member 2% or the lever 21%, can beguided laterally, by providing two guide rails projecting verticallyupward from the base plate with each guide rail coacting with a sideface of the respective part. More particularly, as shown in FIG. 4, theflange of eye 19 extends upwardly as shown at 19a with the upwardlyextending component having a slot in which the pressure member $51 isguided laterahy. Hence, the slot of the component 1% constitutesvertically extending rails for guiding the pressure member.

\Vhen the binding is to be attached, the selector lever 216 is initiallyswung into the position shown in FIG. 10. After the ski boot has beenpositioned with the toe of its sole under the torsion toe clamp mountedforward on the ski, the heel portion 7 is lowered, as indicated by arrow257. During this action the pressure member 263 is pressed rearwardagainst the spring action of the cable 226. The fitting 2426a engagesthe slot 259 in the flange 253 and is thus placed automatically into acentral position on the ski. 'When the heel portion rests on the ski,the pressure member 208 occupies the position directly behind the heelfitting 2 35a, as shown in full lines in FIG. 12. To hook the binding,i.e., to place the cylinder Zilba into the recess 2th; of the fittingEllen, it is merely necessary for the skier to pull on the latch strap26% whose lower loop passes through hollow pivot pin 2139 serving as ahinge pin for the pressure member With the pulling upward of the lever21% by means of the latch strap 26%, the pressure member 2% is pressedforward through the spring action of the cable 226 as soon as thecylinder 283a has been raised above the recess 2%. The skier merely hasto release the latch strap 26%, whereupon the cylinder 292 a, engagesthe recess 29% whereby the attachment of the bindin is completed. Thelatch strap 2-56 is attached to the boot in the customary manner bymeans of a strap 261, as is shown in FIGS. 13-15.

in order to be able to make the hold-down force acting on the heelsomewhat stronger or weaker, as desired, for climbing, the tension ofthe spring 213 can be changed by the adjustment of the threaded socket256 along the thread 217a. For this purpose, the U-shaped bolt 217 isfirst lifted from the recess 216a and then the hooks 235 are releasedfrom the eyes 219. After the adjustment, the remounting is accomplishedby the reversal of the above steps.

The mode of operation of the binding of FIGS. 10-12 is the same asdescribed with reference to FIG. 3. The diiference from the PEG. 3embodiment consists only in that a special spring 21a is provided forpulling the presselector lever 21% swung into the downhill position.

ber.

7 l1 sure member 8 downward at the last part of its travel, while inFIGS. l()l2 a special spring is not present. The eifect of the spring21a in FIG. 3 is obtained in FIGS. l12 by the lateral deflection of thespring 218.

In FIG. 13, the safety binding is illustrated wtih the In this position,the pressure member 2% is held onto the ski with a force correspondingto the point I in PEG. 3a.

The position of the heel portion 7 in FEG. l4 corresponds to the pointIV in FIG. 3a, in which the connecting line between the suspensionpoints of the spring 218 passes through the pivot point 215 of theselector lever.

The position of the heel portion 7 in FIG. 15 corresponds to a pointdirectly below the releasing point 111, in FIG. 3a. The position of theheel portion 7, shown in FIG. 15 is the highest position at which thecylinder can still engage the recess 2%. In this position, the rim ofthe recess 2% extends into notch 23817 in the pressure member 2498 abovethe cylinder 2498a. Beyond this position, the recess 2% moves along path225 and the cylinder 2984: along path 22 and the same separate, at whichtime the heel portion is released from the pressure mem- It can also beseen in FIG. 15 that in this position of the heel portion, 7, the cable226 has bent the springs 213 forward, with the lateral deflection of thesprings 218 corresponding to the tensioning of the spring 21a in FIG. 3.

The invention is not to be confined to any strict conformity to theshowings in the drawings but changes or modifications may be madetherein so long as such changes or modifications mark no materialdeparture from the spirit and scope of the appended claims.

I claim:

1. A safety binding for holding a ski to a boot, including means forholding the toe of the boot to the ski, pressure means adjacent the rearof the boot and above the ski adapted to engage and press upon the heelof the boot, lever means pivotally mounted to the ski to lie above theski and swingable in a vertical longitudinal plane, means pivotallymounting the pressure means'to the lever means for swinging movement inthe same plme as the lever means, a selector lever pivotally mounted toone of said means and movable between a position nearer the pivotalmounting of the lever means to the ski and a position remoter from thepivotal mounting of lever means to the ski, spring means operablycoupled at one end to the selector lever and at the other end to theski, the pivotal mountings of the selector lever being so disposed thatsaid spring means loads the selector lever when the selector lever is inthe position remoter from the pivotal mounting of the lever means to theski for a downhill run with said pivotal mounting of the selector leverpassing across a line extending between the coupling points of thespring means to the selector lever and the ski when the heel of the bootbeing raised from the ski exceeds a predetermined distance whereby theselector lever upon exceeding such predetermined distance automaticallymoves to the position nearer the pivotal mounting of the lever means tothe ski for climbing and cross-country travel with said pressure meanspressing upon the heel with lesser pressure in such latter position.

2. A ski binding as claimed in claim 1 wherein said selector lever andpressure means are constructed and arranged so that said pressure meansforcibly moves the selector lever from the position remoter from thepivotal mounting of the lever means to the ski to a point beyond thedead center position when the heel of the boot is raised a predetermineddistance from the ski.

3. A ski binding as claimed in claim 1 further including means operablycoupled with the pressure means for limiting the free swinging movementof the pressure means in upward direction.

4. A ski binding as claimed in claim 3 in which said limiting meansincludes an elastic component secured i2 to the pressure means at apoint between the pivotal mounting of the pressure means to the levermeans and the point of engagement of the pressure means with the heel ofthe boot, with said elastic component serving to urge the pressure meansin a direction towards the ski.

5. A ski binding as claimed in claim 4 in which elastic component in itsuntensioned condition is of such length that said component begins totransmit a force upon the pressure means only when the boot heel hasbeen raised from the ski a predetermined distance.

6. A ski binding as claimed in claim 5 including a movement transmittingmember attached to the pressure means and having its free end connectedlaterally within the spring means at a point located between the ends ofthe spring means for deflecting the spring means laterally.

7. A ski binding as claimed in claim 6 including a relatively stiffmember which tends to swing the pressure means in a direction towardsthe boot heel so long as the elastic component is untensioned.

8. A ski binding as claimed in claim 1 including a base plate on the skirearwardly of the boot with said base plate adapted to support the levermeans and the other end of the spring means, a vertical flange at theforward end of the base plate and provided with a curved surface adaptedto conform to the contour of the boot heel, said flange serving as arear support for the boot heel and having a slot which is of widerdimensions adjacent the top thereof, and a fitting on the heel of theboot for engagement by the pressure means with said slot receiving saidfitting.

9. A ski binding as claimed in claim 1 in which said spring meansincludes a helical spring positioned on each side of the selector lever,a cap threaded into the uppermost convolutions of each helical spring, aU-shaped member extending transversely of the ski at the upper end ofthe selector lever and each leg of the U-shaped member threadedlyengaging each cap, a pair of eyelets on the ski, and a hook adjacent thelower end of each helical spring for engaging each eyelet with saidU-shaped member maintaining the helical springs under tension.

10. A ski binding as claimed in claim 1 including a shoe on the lever soarranged that when the selector lever is in the position adjacent thepivotal mounting of the lever means to the ski, the spring means isdeflected laterally for increasing the lever when the boot heel israised from the ski a predetermined distance.

11. A ski binding as claimed in claim 1 including vertically extendingrails for guiding one of the means of the binding.

12. A safety binding for holding a ski to a boot, including clamp meanson the ski for holding the toe of the boot, a base plate secured to theski rearwardly of the boot, a vertical support on the base plate, alever pivotally connected to the support adjacent the upper end thereoffor swingmg movement in a vertical longitudinal plane, a vertical flangeat the forward end of the base plate and provided with a curved surfaceadapted to conform to the contour of the heel of the boot, said flangeserving as a rear support for the boot heel and provided with a slottherein, a fitting on the boot heel received by the slot, pressure meansadapted to engage said fitting, means pivotally connecting the pressuremeans to the free end of said lever for swinging movement in the sameplane as the lever, a selector lever pivotally connected adjacent itslower end to said lever intermediate the ends of said lever and movablebetween a position adjacent the pivotal connection of the lever to theverti cal support and a position adjacent the pivotal connection of thepressure means to said lever, a helical spring positioned on each sideof said selector lever, a cap threaded into the uppermost convolutionsor" each helical spring, a U-shaped member extending transversely of theski at the upper end of the selector lever and each leg of the U-shapedmember threadedly engaging each cap, a pair of eyelets on said base, anda hook on the lower 13 end of each helical spring for engaging eacheyelet with said U-shaped member maintaining the helical springs undertension, the arrangement being such that the helical springs load theselector lever when the selector lever is in the position adjacent thepivotal connection of the pressure means to said lever with the pivotalconnection of the selector lever to the said lever passing across a lineextending between the center line of the crosspiece of the U-sl apedmember and the connections of the springs to the eyelets when the heelof the boot being raised fiom the ski exceeds a predetermined distancewhereby the selector upon exceeding such predetermined distanceautomatically moves to the position adjacent the pivotal mounting of thelever to the vertical support and with the pressure means pressing uponthe heel fitting With lesser pressure in such latter position.

References Cited in the file of this patent UNITED STATES PATENTS2,396,373 Henrichsen Mar. 12, 1946 2,610,861 Campbell Sept. 16, 19522,823,922 Berlenbach Feb. 18, 1958 2,851,278 Berlenbach Sept. 9, 1958FOREIGN PATENTS 171,853 Austria July 10, 1952 1,206,878 France Aug. 31,1959

1. A SAFETY BINDING FOR HOLDING A SKI TO A BOOT, INCLUDING MEANS FORHOLDING THE TOE OF THE BOOT TO THE SKI, PRESSURE MEANS ADJACENT THE REAROF THE BOOT AND ABOVE THE SKI ADAPTED TO ENGAGE AND PRESS UPON THE HEELOF THE BOOT, LEVER MEANS PIVOTALLY MOUNTED TO THE SKI TO LIE ABOVE THESKI AND SWINGABLE IN A VERTICAL LONGITUDINAL PLANE, MEANS PIVOTALLYMOUNTING THE PRESSURE MEANS TO THE LEVER MEANS FOR SWINGING MOVEMENT INTHE SAME PLANE AS THE LEVER MEANS, A SELECTOR LEVER PIVOTALLY MOUNTED TOONE OF SAID MEANS AND MOVABLE BETWEEN A POSITION NEARER THE PIVOTALMOUNTING OF THE LEVER MEANS TO THE SKI AND A POSITION REMOTER FROM THEPIVOTAL MOUNTING OF LEVER MEANS TO THE SKI, SPRING MEANS OPERABLYCOUPLED AT ONE END TO THE SELECTOR LEVER AND AT THE OTHER END TO THESKI, THE PIVOTAL MOUNTINGS OF THE SELECTOR LEVER BEING SO DISPOSED THATSAID SPRING MEANS LOADS THE SELECTOR LEVER WHEN THE SELECTOR LEVER IS INTHE POSITION REMOTER FROM THE PIVOTAL MOUNTING OF THE LEVER MEANS TO THESKI FOR A DOWNHILL RUN WITH SAID PIVOTAL MOUNTING OF THE SELECTOR LEVERPASSING ACROSS A LINE EXTENDING BETWEEN THE COUPLING POINTS OF THESPRING MEANS TO THE SELECTOR LEVER AND THE SKI WHEN THE HEEL OF THE BOOTBEING RAISED FROM THE SKI EXCEEDS A PREDETERMINED DISTANCE WHEREBY THESELECTOR LEVER UPON EXCEEDING SUCH PREDETERMINED DISTANCE AUTOMATICALLYMOVES TO THE POSITION NEARER THE PIVOTAL MOUNTING OF THE LEVER MEANS TOTHE SKI FOR CLIMBING AND CROSS-COUNTRY TRAVEL WITH SAID PRESSURE MEANSPRESSING UPON THE HEEL WITH LESSER PRESSURE IN SUCH LATTER POSITION.